underground has the lyrics and is really hip hop
mainstream is just something wif a sick beat and thats it, no good lyrics, just enough to fill up space.

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kidcard7692: cock-a-doodle niggaz
da916_nigga: I hate whites, blacks, and mexicans...but I love my greens
kidcard7692: Niggas dont eat sprinkles
kidcard7692: i just fell going up the stairs